The 49ers became the first team in NFL history to win 15 games in a regular season and to win 18 in an entire season (including the post-season). Additionally, two major offensive records were set this season, with quarterback Dan Marino establishing a new single-season passing yards record with 5,084 (later broken by Drew Brees and Tom Brady in 2011), and Eric Dickerson establishing a new single-season rushing yards record with 2,105.

The penalty for a kickoff or onside kick that goes out of bounds is 5 yards from the previous spot and a re-kick must be made. However, if the second (or more) kickoff or onside kick goes out of bounds, the receiving team may choose instead to take possession of the ball at the out of bounds spot.

Leaping to try to block a field goal or an extra point is illegal unless the defensive player was lined up at the line of scrimmage.

A kicker or holder who fakes being roughed or run into by a defensive player can receive an unsportsmanlike conduct penalty.

Unsportsmanlike conduct will also be called for any prolonged, excessive, or premeditated celebration by individual players or a group of players. This is usually referred to as the "Mark Gastineau Rule" because a major reason why this change was made was to stop him from performing his signature "Sack Dance" every time after he sacked an opposing quarterback.